GREAT FALLS, Mont. — Those scratch-and-sniff cards the energy company sends to customers to teach them to recognize the artificial smell added to natural gas? Turns out they work pretty well.

Energy West general manager Nick Bohr tells the Great Falls Tribune (http://gftrib.com/18u3gYG ) that workers recently discarded several boxes of expired scratch-and-sniff cards in Great Falls. But when the garbage truck picked them up and compressed the load Bohr says "it was the same as if they had scratched them."